Index funds allow an investor to invest in a single investment instrument that tracks the performance of a portfolio of investments. In general, an index fund issues shares that represent a fractional interest in a portfolio of investments, which are weighted similar to those portfolio of investments as weighted for a published securities index, e.g., stock index, in order to mirror, track, or generally correspond to the price and/or yield performance of the stock index.
One example of an index fund is a Standard & Poor's Depository Receipt (“SPDR”). An SPDR is a type of security known as a portfolio depository receipt (also known as an Exchange Traded Fund), which represents an undivided ownership interest in a portfolio of stocks held by the SPDR Trust. The SPDR Trust holds a portfolio of stocks that is intended to mirror, track, or generally correspond to the price and/or yield performance of the S&P 500 Index.
Securities, like SPDRs, may trade on a stock exchange, a securities market or an electronic communication network. The price of such securities during intra-day trading is determined by supply and demand. In particular, depository receipts issued by the SPDR Trust may be generated or redeemed on any business day at the next calculated net asset value (NAV), but only in “creation units” of 50,000 SPDR shares. SPDR creation units are generated or redeemed through an in-kind transfer of the basket of stocks that correspond to the stocks listed in the S&P 500 Index. Although the NAV of the SPDR Trust is only published at the close of every business day, the value of the corresponding S&P 500 index is published continuously throughout each trading day and distributed electronically to brokers and dealers throughout the world. Similarly, a number corresponding to the intra-day value of each SPDR share, based on the most recently traded prices of the stocks of the S&P 500 index in the current day's SPDR creation unit, is ordinarily published at 15 second intervals throughout the trading day.
Index futures contracts and index options provide other techniques for investors to invest, trade, or hedge based on the performance of an index. An index futures contract is a futures contract on a financial index such as the S&P 500 index, whereas index options are instruments that give the holder the right to receive cash settlements based on changes in the underlying index on which the option is based. A call index option would ordinarily give a payout if the index rises above its strike price, whereas a put index option would give a payout if the index fails, below its strike price.